Textbook information is available in the course outlines for individual papers online. You can also discuss the requirements with your lecturer or the teaching department.
Each textbook is rated as to how important it is for the course. You should get those marked Essential, however you may not need to purchase the Supplementary or Highly Recommended books. Textbooks are available from the University of Otago Library for borrowing but often only for a limited time because of demand.
You can purchase textbooks from the University Book Shop (UBS). Search for textbooks on the UBS website:
Course readers are collections of readings relevant to a particular paper, made up of various articles and excerpts from published material. Course readers are compiled by teaching departments for use in conjunction with textbooks and lecture material. Not all papers use course readers.
Some departments provide course readers directly to students, but students normally purchase course readers from the Uniprint shop in the Central Library at the beginning of the semester. You will be advised by your lecturer when your course reader is available to buy.